Recent spread of HD (High Definition) broadcast services nationwide and worldwide makes more users familiar with high-resolution, high-quality images, and many organizations put more efforts to development of next-generation imaging devices. Further, more interest is oriented towards UHD (Ultra High Definition) having 4 times or more resolution than HDTV, as well as HDTV, so that image compression technologies for higher-resolution, higher-quality images are demanded.
For purposes of image compression, an inter prediction for predicting a pixel value included in a current picture from a temporally previous and/or subsequent picture, an intra prediction for predicting a pixel value included in a current picture by using pixel information in the current picture, and an entropy encoding for assigning a shorter code to a more frequent symbol while assigning a longer code to a less frequent symbol may be used.